Add an interface to gather text surrounding the selection.

content/public/browser/android/content_view_core.h

Index: content/public/browser/android/content_view_core.h
diff --git a/content/public/browser/android/content_view_core.h b/content/public/browser/android/content_view_core.h
index 1501985b8a53bfa15439eb84ada178e1b8f34d63..a6e4ab1d737df97ae024f26e6eb802d4323a71d9 100644
--- a/content/public/browser/android/content_view_core.h
+++ b/content/public/browser/android/content_view_core.h
@@ -68,6 +68,15 @@ class CONTENT_EXPORT ContentViewCore {
       const gfx::Vector2dF& scroll_offset,
       float page_scale_factor)> UpdateFrameInfoCallback;
 
+  // Text surrounding selection.
+  typedef base::Callback<void(const base::string16& content,
+                              int start_offset,
+                              int end_offset)>
+      TextSurroundingSelectionCallback;
+  virtual void RequestTextSurroundingSelection(
+      int max_length,
+      const TextSurroundingSelectionCallback& callback) = 0;
+
  protected:
   virtual ~ContentViewCore() {};
 };